JP2004135159A - Radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform radio communication with a radio terminal by a plurality of channels and to enhance economical efficiency. <P>SOLUTION: A leakage waveguide 12 is arranged indoors 11 where a wireless LAN is operated, one end of the leakage waveguide is connected with a radio base station device 13 and the other end is connected with a termination device 14. The radio base station device 13 performs the radio communication with radio terminals 17-1, 17-2, 17-3, 17-4 with different use channels respectively as successively and repeatedly switching four channels (CH34, CH38, CH42, CH46) to be used in a wireless LAN system for indoors of 5GHz band by every fixed time T. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wireless communication system including a wireless base station that performs wireless communication with a wireless terminal device via a leaky transmission path provided indoors.
[0002]
[Prior art]
As a wireless communication system that performs wireless communication between a wireless base station device and a wireless terminal device indoors, a base station transmits and receives via an antenna for performing wireless communication with a terminal station in a service area, A relatively high-output power transmission / reception means for performing wireless communication with a terminal station having a dead area where radio waves radiated from the base station do not reach effectively; By disposing an antenna or a leaky feeder according to the shape, and connecting the antenna or the leaky feeder and the transmitting / receiving means via the feeder of the base station with a feeder having a predetermined attenuation constant and a predetermined length. It is known that the output level of the radio wave radiated from the antenna or the leaky feed line is set not to exceed the level of the radio wave radiated from the transmitting / receiving means via the antenna of the base station. (E.g., see Patent Document 1.).
[0003]
[Patent Document 1]
JP-A-06-188821 (paragraph "0006" etc.)
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional technique, in addition to a wireless LAN system in which a normal base station is installed, a leaky feeder line is further arranged in an insensitive area, and a secondary wireless facility serving as a dedicated transmission means is provided in this. As a result, the facilities were large and economical efficiency was poor. Further, there is a problem that only one channel can be used in the area where the leakage power supply line is installed.
[0005]
Therefore, the present invention enables wireless communication with a wireless terminal device through a plurality of channels. For example, a wireless terminal device in which a communicable channel different from the channel of an installed wireless terminal device is set moves to a communication range. Provided is a wireless communication system that can cope with the situation when the mobile phone enters the network and can improve economic efficiency.
[0006]
[Means for Solving the Problems]
According to the present invention, a leaky transmission line such as a leaky waveguide or a leaky coaxial cable, which is disposed indoors and functions as an antenna, is connected to the leaky transmission line, and a channel to be used is set via the leaky transmission line. And a wireless base station device for performing wireless communication with the plurality of wireless terminal devices, and the wireless base station device switches a channel for wireless communication at predetermined time intervals.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First Embodiment)
As shown in FIG. 1, a leaky waveguide 12 as a leaky transmission line is arranged in a meandering manner inside a store or the like, for example, on a ceiling portion of an indoor 11 that operates a wireless LAN.
[0008]
The leaky waveguide 12 is disposed, for example, on the front side of the ceiling panel, behind the ceiling panel, or in the ceiling panel. If there is no ceiling panel, the leaky waveguide 12 is disposed in the upper space of the indoor 11 so as to be hung inside the roof.
Although a leaky coaxial cable can be used as the leaky transmission line, a leaky waveguide having a small transmission loss is more suitable for a low transmission power system such as a wireless LAN.
[0009]
The leaky waveguide 12 has one end connected to the wireless base station device 13 and the other end connected to a terminator 14 as a terminating load having a load resistance value equal to the characteristic impedance of the waveguide. The wireless base station device 13 is installed on a wall surface where maintenance work is easy. In addition, you may install in a ceiling panel etc.
[0010]
As shown in FIG. 2, the leaky waveguide 12 is formed by providing a predetermined length of slots 12b at regular intervals in a tubular conductor 12a and covering the whole with a coating material 12c. Radio waves are transmitted and received between the inside of the waveguide and the external space via the slot 12b.
[0011]
The radio wave radiation characteristic of the leaky waveguide 12 is different from that of a general single antenna such as a whip antenna or a dipole antenna, and has a radiation pattern as shown in FIG. That is, the radiation pattern is fan-shaped when viewed from the axial direction of the leaky waveguide 12, and extends over the entire waveguide. The electric field intensity is large near the leaky waveguide 12, and the electric field intensity distribution gradually weakens as the distance increases.
[0012]
In the case of a 2.4 GHz band or a 5 GHz band indoor wireless LAN system having a transmission power of several tens to several hundreds mW, the interval between the leaky waveguides 12 arranged in a meandering manner should be set to about 6 m to 10 m. This is reasonable in terms of both communication performance and economy.
[0013]
The wireless base station device 13 is connected to a LAN cable 15 and a power cable 16. A plurality of, for example, three wireless terminal devices 17-1, 17-2, and 17-3 that wirelessly communicate with the wireless base station device 13 are fixedly arranged on the floor of the indoor 11.
[0014]
In a wireless LAN system having such a configuration, for example, a 5 GHz band indoor wireless LAN system used in Japan, 34 channels (5.170 GHz), 38 channels (5.190 GHz), 42 channels (5.210 GHz), Four channels of 46 channels (5.230 GHz) are allocated.
[0015]
Now, 34 channels are set as channels used for the wireless terminal device 17-1, 38 channels are set as channels used for the wireless terminal device 17-2, and 42 channels are set as channels used for the wireless terminal device 17-3. Is set.
[0016]
In this wireless LAN system, information transmitted to the wireless base station device 13 by the LAN cable 15 is modulated by OFDM (Orthogonal Frequency Division Multiplexing Modulation), and transmitted to the leaky waveguide 12 as a 5 GHz band high frequency signal. You. While this high-frequency signal propagates through the leaky waveguide 12, a part of the high-frequency signal is radiated from a large number of slots 12b as radio waves to an angle range of about 180 degrees in the space in the floor surface direction.
[0017]
The receiving antennas of the wireless terminal devices 17-1 to 17-3 receive a large number of incoming waves, which are radiated from a large number of slots 12b, respectively, and the phase difference between the incoming waves is very small. Because they are different, they can be considered almost continuous. Therefore, even if there are some combinations of arriving waves that completely cancel each other out with a phase difference of 180 degrees at the receiving antenna, there is effective reception power due to the majority of the remaining arriving waves.
[0018]
For example, in the wireless terminal device 17-1, of the slots 12b of the leaky waveguide 12, a plurality of transmission waves radiated from the relatively close slot groups 18a and 18b are particularly strongly received as arriving waves. . Although there is a time difference between the transmitted waves and the arrival at the receiving point, the distance between the leaky waveguides 12 is 10 m, the height of the leaky waveguide 12 from the floor is 3 m, and Assuming that the distance between the slot group 18a and the slot group 18b is 20 m, the maximum value of the time difference between the incoming waves received by the wireless terminal device 17-1 is about 90 nsec.
[0019]
OFDM is a type of multicarrier transmission system, and transmission data is transmitted by a number of subcarriers orthogonal to each other. Then, each subcarrier transmits a modulation symbol (multi-code) composed of two parts, an effective symbol section as shown in FIG. 4 and a guard section in which a part of the effective symbol section is copied.
[0020]
In the OFDM standard used for the wireless LAN, the guard section that can eliminate the influence of the delay wave is set to 800 nm. Since the OFDM method has resistance to a delayed wave arriving in a guard section in a demodulation process on the receiving side, there is a plurality of time differences on the receiving side when there are a plurality of transmission wave sources or when there is a multipath due to a reflected wave. Even if a radio wave is received, deterioration of transmission quality due to intersymbol interference in the demodulation stage is small.
[0021]
Therefore, when a large number of arriving waves having continuously different phases are received, normal demodulation is performed if the maximum time difference between a plurality of arriving waves occupying main power is within the guard interval. Therefore, information can be reliably obtained by the wireless terminal device 17-1 receiving the incoming waves from the slot group 18a and the slot group 18b on the leaky waveguide 12 and performing OFDM demodulation. Further, even if the transmission wave from the slot group 18a is completely blocked by an obstacle of a person or furniture, the transmission wave from the remaining slot group 18b reaches the receiving antenna.
[0022]
Further, as shown in FIG. 5A, the radio base station apparatus 13 repeatedly switches the channel to be used at regular time intervals T in the order of CH34 → CH38 → CH42 → CH46 → CH34. Accordingly, as shown in FIG. 5B, the wireless terminal device 17-1 can communicate when the wireless base station device 13 switches to the 34 channel, and the wireless terminal device 17-2 communicates with the wireless terminal device 17-2 in FIG. As shown in FIG. 5C, when the radio base station apparatus 13 switches to channel 38, communication becomes possible, and the radio terminal apparatus 17-3 communicates with the radio base station apparatus as shown in FIG. Communication becomes possible when the device 13 switches to 42 channels.
[0023]
As described above, since the wireless base station apparatus 13 performs communication with the wireless terminal apparatuses by switching four channels, for example, if five wireless terminal apparatuses are arranged for each channel, a total of 20 wireless terminal apparatuses are used. The wireless terminals can be arranged, and the number of wireless terminal devices to be arranged can be increased.
[0024]
In the 5 GHz band wireless LAN system, when four channels are switched, a decrease in throughput is expected as compared with a case where the channels are fixed. However, the transmission rate in the 5 GHz band is 54 Mbps at the maximum, and when four channels are switched, the throughput per channel becomes 54/4 = 13.5 Mbps. On the other hand, the transmission rate of the 2.4 GHz band wireless LAN system currently in widespread use is 11 Mbps at the maximum, and a sufficient throughput can be obtained even when adopting a method of switching four channels in a 5 GHz band wireless LAN system.
[0025]
In this wireless LAN system, FIG. 1 shows an area where the wireless base station device 13 is performing wireless communication while switching channels with the wireless terminal devices 17-1, 17-2, and 17-3 via the leaky waveguide 12. As shown by the arrow, when the mobile radio terminal device 17-4 in which CH46 is set as the use channel enters, the radio base station device 13 switches to the 46 channel for the mobile radio terminal device 17-4. Wireless communication becomes possible.
[0026]
In this way, the wireless base station apparatus 13 moves and communicates with the wireless terminal apparatus 17-4 in which a channel different from the channels of the installed wireless terminal apparatuses 17-1, 17-2, and 17-3 is set. We can deal with cases when we enter the area.
[0027]
In addition, in this wireless LAN system, it is not necessary to arrange a plurality of wireless equipments such as a main station and a slave station in the indoor 11 and equipment cost is not required, so that economic efficiency can be improved. In addition, since the leaky waveguide 12 is used as an antenna of the wireless base station device 13, even if many furnitures are present in the indoor 11, the wireless terminal devices 17-1 and 17 are scattered in the indoor 11. -2, 17-3 can be reliably ensured. Therefore, the generation of the dead area in the indoor 11 can be eliminated, and high-speed communication without intersymbol interference can be realized at low cost.
[0028]
(Second embodiment)
The same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
As shown in FIG. 6, the leaky waveguide 12 has one end connected to the wireless base station device 23-1, and the other end connected to another wireless base station device 23-2 provided in place of the terminator 14. are doing.
[0029]
Each of the radio base station apparatuses 23-1 and 23-2 is installed on a wall surface where maintenance work is easy. In addition, you may install in a ceiling panel etc. The wireless base station device 23-1 is connected to a LAN cable 15 and a power cable 16, and the wireless base station device 23-2 is connected to a LAN cable 25 and a power cable 26.
[0030]
The wireless base station device 23-1 is assigned 34 channels in the 5 GHz band indoor wireless LAN system, and the wireless base station device 23-2 is assigned 38 channels.
[0031]
In such a configuration, for example, if 34 channels are set as channels used for the wireless terminal devices 17-1 and 17-2 and 38 channels are set as channels used for the wireless terminal device 17-3, The wireless base station device 23-1 wirelessly communicates with the wireless terminal devices 17-1 and 17-2 via the leaky waveguide 12. The wireless base station device 23-2 wirelessly communicates with the wireless terminal device 17-3 via the leaky waveguide 12.
[0032]
Accordingly, two channels can be simultaneously communicated indoors using the two wireless base station devices 23-1 and 23-2, and the throughput can be improved as compared with the case where communication is performed with one wireless base station device. Also, when a wireless base station device using 34 or 38 channels enters from outside the communication range into the communication range of the indoor 11, communication with the wireless base station device becomes possible.
[0033]
Also in this embodiment, it is not necessary to arrange a plurality of radio equipment, and the economy can be improved. Further, the radio wave propagation paths between the radio terminal devices 17-1, 17-2, and 17-3 can be reliably secured, and high-speed communication without intersymbol interference can be realized at low cost. This is the same as the embodiment.
[0034]
In this embodiment, two channels in the 5 GHz band indoor wireless LAN system are assigned to each of the wireless base station devices 23-1 and 23-2. However, the present invention is not limited to this. Two channels in the indoor wireless LAN system may be allocated.
[0035]
(Third embodiment)
The same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
As shown in FIG. 7, the leaky waveguide 12 has one end connected to the pair of wireless base station devices 33-1 and 33-2 via the duplexer 19, and the other end connected to the terminator 14. Connected.
[0036]
Each of the wireless base station devices 33-1 and 33-2 is installed on a wall surface where maintenance work is easy. In addition, you may install in a ceiling panel etc. The wireless base station devices 33-1 and 33-2 are connected to a LAN cable 15 and a power cable 16, respectively.
[0037]
The wireless base station device 33-1 is assigned 34 channels in a 5 GHz band indoor wireless LAN system, and the wireless base station device 33-2 is assigned 38 channels.
[0038]
In such a configuration, for example, if 34 channels are set as channels used for the wireless terminal devices 17-1 and 17-2 and 38 channels are set as channels used for the wireless terminal device 17-3, The wireless base station device 33-1 performs wireless communication with the wireless terminal devices 17-1 and 17-2 via the leaky waveguide 12. The wireless base station device 33-2 wirelessly communicates with the wireless terminal device 17-3 via the leaky waveguide 12.
[0039]
Thus, two channels can be simultaneously communicated indoors using the two wireless base station devices 33-1 and 33-2, and the throughput can be improved as compared with the case where communication is performed with one wireless base station device. Also, when a wireless base station device using 34 or 38 channels enters from outside the communication range into the communication range of the indoor 11, communication with the wireless base station device becomes possible.
[0040]
Also in this embodiment, it is not necessary to arrange a plurality of radio equipment, and the economy can be improved. Further, the radio wave propagation paths between the radio terminal devices 17-1, 17-2, and 17-3 can be reliably secured, and high-speed communication without intersymbol interference can be realized at low cost. This is the same as the embodiment.
[0041]
In this embodiment, two channels in the 5 GHz band indoor wireless LAN system are assigned to each of the wireless base station devices 33-1 and 33-2, but the present invention is not limited to this. Two channels in the indoor wireless LAN system may be allocated.
[0042]
(Fourth embodiment)
The same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
As shown in FIG. 8, one end of the leaky waveguide 12 is connected to a pair of wireless base station devices 33-1 and 33-2 via the duplexer 19, and the other end is connected to the duplexer 29. It is connected to a pair of wireless base station devices 43-1 and 43-2 via.
[0043]
Each of the wireless base station devices 33-1, 33-2, 43-1 and 43-2 is installed on a wall surface where maintenance work is easy. In addition, you may install in a ceiling panel etc. The wireless base station devices 33-1 and 33-2 are connected to a LAN cable 15 and a power cable 16, respectively, and the wireless base station devices 43-1 and 43-2 are connected to a LAN cable 25 and a power cable 26, respectively. are doing.
[0044]
The wireless base station device 33-1 is assigned 34 channels in a 5 GHz band indoor wireless LAN system, the wireless base station device 33-2 is assigned 38 channels, and the wireless base station device 43-1. 1 is allocated 42 channels, and the radio base station apparatus 43-2 is allocated 46 channels.
[0045]
In such a configuration, for example, 34 channels are set as channels used for the wireless terminal device 17-1, 38 channels are set as channels used for the wireless terminal device 17-2, and the wireless terminal device 17-3 is set for the wireless terminal device 17-3. If 42 channels are set as channels to be used, the wireless base station device 33-1 performs wireless communication with the wireless terminal device 17-1 via the leaky waveguide 12.
[0046]
The wireless base station device 33-2 wirelessly communicates with the wireless terminal device 17-2 via the leaky waveguide 12, and the wireless base station device 43-1 communicates with the wireless terminal device 17-2 via the leaky waveguide 12. 3 and wirelessly communicate.
[0047]
Also, as shown by an arrow in FIG. 8, even if the mobile radio terminal device 17-4 in which CH46 is set as the use channel enters the indoor 11 area, the radio base station device 43-2 at this time causes leakage. It communicates wirelessly with the mobile wireless terminal device 17-4 via the waveguide 12.
[0048]
In this way, by arranging the four wireless base station devices 33-1, 33-2, 43-1 and 43-2, all four channels in the indoor wireless LAN system of the 5 GHz band are used in the indoor 11 It becomes possible. Therefore, the throughput can be further improved. Also in this embodiment, it is not necessary to arrange a plurality of radio equipment, and the economy can be improved. Further, the radio wave propagation paths between the radio terminal devices 17-1, 17-2, and 17-3 can be reliably secured, and high-speed communication without intersymbol interference can be realized at low cost. This is the same as the embodiment.
[0049]
In this embodiment, four channels in the 5 GHz band indoor wireless LAN system are assigned to each of the wireless base station devices 33-1 to 33-2. However, the present invention is not limited to this. Instead, a channel in the 2.4 GHz band indoor wireless LAN system may be assigned.
[0050]
In each of the embodiments described above, the present invention is applied to a wireless LAN system, but the present invention is not necessarily limited to this. The present invention can be applied to a wireless communication system not using a LAN.
[0051]
【The invention's effect】
As described above in detail, according to the present invention, a wireless terminal can perform wireless communication with a plurality of channels, for example, a wireless terminal in which a communicable channel different from the channel of an installed wireless terminal is set. It is possible to provide a wireless communication system that can cope with the case where the device moves and enters the communication area and that can improve economic efficiency.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an arrangement relation of respective parts according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a leaky waveguide in the embodiment.
FIG. 3 is a view showing a radio wave radiation pattern of the leaky waveguide according to the embodiment.
FIG. 4 is a diagram showing a configuration of a modulation symbol of the OFDM system used in the communication of the embodiment.
FIG. 5 is a diagram showing a relationship between channel switching of the wireless base station device and channels used by each wireless terminal device in the embodiment.
FIG. 6 is a perspective view showing an arrangement relation of respective parts according to a second embodiment of the present invention.
FIG. 7 is a perspective view showing an arrangement relation of respective parts according to a third embodiment of the present invention.
FIG. 8 is a perspective view showing an arrangement relation of respective parts according to a fourth embodiment of the present invention.
[Explanation of symbols]
11 indoor 12 leaky waveguide 13 wireless base station devices 17-1 to 17-4 wireless terminal device

Claims (4)

A leaky transmission line that is installed indoors and functions as an antenna, and a wireless base station device that connects to the leaky transmission line and performs wireless communication with a plurality of wireless terminal devices that are set to use channels via the leaky transmission line And the wireless base station apparatus switches a channel for wireless communication at regular time intervals. A leaky transmission line that is provided indoors and functions as an antenna, and is connected to each end of the leaky transmission line, and wirelessly communicates with a plurality of wireless terminal devices that are set to use channels via the leaky transmission line. A wireless communication system comprising a wireless base station device, wherein the wireless base station devices use different channels for wireless communication. A leaky transmission line that is disposed indoors and functions as an antenna, a duplexer connected to one end of the leaky transmission line, connected to the leaky transmission line via the duplexer, and used through the leaky transmission line A wireless communication system, comprising: a plurality of wireless base station apparatuses for performing wireless communication with a plurality of wireless terminal apparatuses to which channels are set, wherein the wireless base station apparatuses use different channels for wireless communication. A leaky transmission line disposed indoors and functioning as an antenna, a duplexer connected to each end of the leaky transmission line, and a leaky transmission line connected to the leaky transmission line via one duplexer. Connected to the leaky transmission line via a plurality of wireless base station devices that perform wireless communication with a plurality of wireless terminal devices set with use channels via the other and the other duplexer. A wireless communication system, comprising: a plurality of wireless base station apparatuses for performing wireless communication with a plurality of set wireless terminal apparatuses, wherein each of the wireless base station apparatuses has a different channel for wireless communication.
Wireless communication system.

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